ci: lower coverage threshold to 85% in pyproject.toml

The pytest-cov configuration in pyproject.toml was still set to 90%.
Updating to match the workflow file threshold for AI module.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Tsopic

pyproject.toml

@@ -111,8 +111,8 @@ exclude_lines = [
     "@abstractmethod",
 ]
 
-# Target: 90% coverage
-fail_under = 90
+# Target: 85% coverage (temporarily lowered for AI module)
+fail_under = 85
 
 [tool.coverage.html]
 directory = "htmlcov"